Occupational hearing loss
Hearing loss - occupational; Noise-induced hearing loss; Noise notch
Occupational hearing loss is damage to the inner ear from noise or vibrations due to certain types of jobs.
The ear consists of external, middle, and inner structures. The eardrum and the 3 tiny bones conduct sound from the eardrum to the cochlea.
Causes
Over time, repeated exposure to loud noise or music can cause hearing loss.
Sounds above 80 decibels (dB, a measurement of the loudness or strength of sound vibration) may cause vibrations intense enough to damage the inner ear. This is more likely to happen if the sound continues for a long time.
- 90 dB -- a large truck 5 yards (4.5 meters) away (motorcycles, snowmobiles, and similar engines range from 85 to 90 dB)
- 100 dB -- some rock concerts
- 120 dB -- a jackhammer about 3 feet (1 meter) away
- 130 dB -- a jet engine from 100 feet (30 meters) away
A general rule of thumb is that if you need to shout to be heard, the sound is in the range that can damage hearing.
Some jobs carry a high risk for hearing loss, such as:
- Airline ground maintenance
- Construction
- Farming
- Jobs involving loud music or machinery
- Military jobs that involve combat, aircraft noise, or other loud noise posts
In the United States, laws regulate the maximum job noise exposure that it is allowed. Both the length of exposure and decibel level are considered. If the sound is at or greater than the maximum levels recommended, you need to take steps to protect your hearing.
We often take for granted all of the sounds around us, the bark of a dog, the buzz of a bee, or the melody of our favorite symphony. Yet for many people, the world is a very quiet place. They've lost the ability to hear sounds in one or both ears. Let's talk about hearing loss. To understand how you lose hearing, you first need to know what normally happens inside your ear when you hear. Say that a fire engine roars past. First, the sound of the siren reaches your eardrum in your outer ear. Your eardrum vibrates, which moves three tiny bones in your middle ear. These bones push the sound along to the cochlea, a fluid-filled chamber in your inner ear. The cochlea is lined with tiny hairs that vibrate when the sound waves hit them. These hairs convert the sound waves into an electrical signal. That's when your brain realizes that a fire engine is headed toward you. Hearing loss can have many different causes. Loud noises, pressure changes while you're scuba diving, or a head injury can all damage the delicate structures in your ear that allow you to hear. Infections like measles, mumps, and meningitis can also damage the ear. Sometimes earwax can build up in your ear and block your hearing like a plug. As you get older, you may gradually lose your hearing, even if you don't have an illness or injury. When the damage or other problem is to your outer or middle ear, it's called conductive hearing loss. For example, your eardrum may not vibrate when you hear sound. Or, the tiny bones in your middle ear may not move sound to the inner ear. Sensorineural hearing loss is caused by a problem in the inner ear. Often it's because the tiny hair cells that move sound through the ear don't work right because of damage or disease, and stem cells in the ear can't keep up with the repair. If you have problems with both your inner and outer ear, then you have mixed hearing loss. So, how do you treat hearing loss? If you're noticing that voices sound fuzzy and you can't make out what people are saying, see your doctor for a hearing test. The doctor will examine your ears, and give you a test called audiometry to check the type and amount of hearing you've lost. You may also have imaging tests such as a CT or MRI scan if you've had a head injury. A hearing aid can amplify sounds to help you hear more clearly. Today's hearing aids are so small they're barely noticeable. If you have a buildup of earwax in your ear, an ear syringe filled with warm water can help flush it out. Sometimes surgery can be done to fix damage in your ear and improve your hearing. Don't accept hearing loss as an inevitable part of growing older. See your doctor for a hearing evaluation. Often, hearing loss that's due to a problem in your outer or middle ear can be reversed. Protect the hearing that you do have by avoiding loud noises, and wearing earplugs when you have to be exposed to loud sounds.
Symptoms
The main symptom is partial or complete hearing loss. The hearing loss will likely get worse over time with continued exposure.
Noise in the ear (tinnitus) may accompany hearing loss.
Exams and Tests
A physical exam will not show any specific changes in most cases. Tests that may be done include:
- Audiology/audiometry
- CT scan of the head
- MRI of the brain
Treatment
The hearing loss is very often permanent. The goals of treatment are to:
- Prevent further hearing loss
- Improve communication with any remaining hearing
- Develop coping skills (such as lip reading)
You may need to learn to live with hearing loss. There are techniques you can learn to improve communication and avoid stress. Many things in your surroundings can affect how well you hear and understand what others are saying.
Using a hearing aid may help you understand speech. You can also use other devices to help with hearing loss. If the hearing loss is severe enough, a cochlear implant may help.
Protecting your ears from any further damage and hearing loss is a key part of treatment. Protect your ears when you are exposed to loud noises. Wear ear plugs or earmuffs to protect against damage from loud equipment.
Be aware of risks connected with recreation such as shooting a gun, driving snowmobiles, or other similar activities.
Learn how to protect your ears when listening to music at home or concerts.
Outlook (Prognosis)
Hearing loss is often permanent. The loss may get worse if you don't take measures to prevent further damage.
When to Contact a Medical Professional
Contact your health care provider if:
- You have hearing loss
- The hearing loss gets worse
- You develop other new symptoms
Prevention
The following steps can help prevent hearing loss.
- Protect your ears when you are exposed to loud noises. Wear proper protective ear plugs or earmuffs when you are around loud equipment.
- Be aware of the risks to hearing from recreational activities such as shooting a gun or driving snowmobiles.
- DO NOT listen to loud music for long periods of time, including using headphones.
References
Arts HA, Adams ME. Sensorineural hearing loss in adults. In: Flint PW, Francis HW, Haughey BH, et al, eds. Cummings Otolaryngology: Head and Neck Surgery. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 152.
Eggermont JJ. Causes of acquired hearing loss. In: Eggermont JJ, ed. Hearing Loss. Cambridge, MA: Elsevier Academic Press; 2017:chap 6.
Le Prell CG. Noise-induced hearing loss. In: Flint PW, Francis HW, Haughey BH, et al, eds. Cummings Otolaryngology: Head and Neck Surgery. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 154.
National Institute on Deafness and Other Communication Disorders (NIDCD) website. Noise-induced hearing loss. NIH Pub. No. 14-4233.
Version Info
Last reviewed on: 5/30/2022
Reviewed by: Josef Shargorodsky, MD, MPH, Johns Hopkins University School of Medicine, Baltimore, MD. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
